Method and apparatus for registering and making-ready printing plates off a press



Oct. 17, 1967 J. w. LENK ETAL 3,347,151 METHOD AND APPARATUS FOR REGISTERING AND MAKING-READY PRINTING PLATES OFF A PRESS Filed April 5, 1966 2 Sheets-Sheet 1 INVENTORS James IV. Len/4 o,

A TT OFlNEY Oct. 17, 1967 J. w. LENK- ETAL 3,347,161 METHOD AND APPARATUS FOR REGISTERING AND MAKING-READ PRINTING PLATES OFF A PRESS 2 Sheets-Sheet 2 Filed April 5. 1966 INVENTORD. James #14 Lenk BY flrf/fl/r /7. Burma:

hrromvev United States Patent f 3,347,161 METHOD AND APPARATUS FOR REGISTERENG AND MAKING-READY PRINTING PLATES OFF A PRESS James W. Lenk, Shawnee Mission, and Arthur H. Burnett, Prairie Viilage, Karts, assignors to Waibert Equipment Company, Kansas City, Mo., a corporation of Missouri Filed Apr. 5, 1966, Ser. No. 549,304 5 (liaims. (Cl. 101-216) ABSTRACT OF THE DISCLOSURE Vertically spaced-apart rotatable cylinders are maintained in the same relative rotational positions and are adapted to receive respective drawsheets thereon, one of the drawsheets having positive dummy thereon and the other one adapted to receive a printing plate. An optical system is located between the cylinders and includes a rst reflector for reflecting an image horizontally from the positive dummy, a semi-transparent reflector for transmitting the dummy image therethrough, and a second reflector reflecting the printing plate image to the semitransparent reflector from which it is reflected horizontally into the path of the dummy image. Ink pick-up and ink applicating rollers are adapted to ink the printing plate with flexographic ink while on the cylinder and a proof sheet cylinder is movably mounted on the apparatus for controlled pressure application against the plate to make proof sheets.

This invention relates to a method of and an appara tus for establishing registration and surface adjustment of printing plates off of a printing press in which the plates are to be subsequently used, so that the plates will yield uniformly printed impressions in registering relation.

In printing in more than one color, a printing plate is required for each color pattern of an original composition, drawing, photograph, or the like, to be reproduced by a printing plate in a rotary cylinder printing press. These plates are usually made of non-rigid materal such as rubber, rubber composition, or the like, capable of being curved about the cylinders of a printing press and secured in proper relation thereon, so that the impressions made thereby will be in proper registry and accurately reproduce a likeness of the original composition.

Likewise, where multicolor printing is produced on a single cylinder press, it is necessary that the plate for each succeeding run must be located in exactly the same position on the cylinder as the plates used in a preceding run, to assure proper registry with the ink impressions of the different runs.

In order to reduce shutdown time of a press, the plates are fixed in registry on mounting or drawsheets, which may be a rubber blanket, tympan or Mylar sheet, or any sheet which is reasonably dimensionally stable. To assure the sheets will be mounted on the cylinders in the same place, the cylinders of the printing press are provided with a row of aligned pins, with the pins on each cylinder being located in identically the same position on all of the cylinders. The drawsheets have a corresponding number of identically located holes punched therein, so that when a drawsheet is applied with the holes passing the pins therein, all of the plates will be located in the same position on the respective cylinders.

In order to locate the printing plates on the drawsheets off the press, various registering apparatus have been used, which usually include at least two cylinders of equal size and having pins conforming in number and spacing with the pins on the press cylinders. The draw- 3,347,153. Patented Get. 17, 1967 sheets may then be mounted on the cylinders in the registering apparatus in the same relative relation that they will assume on the press cylinders. One of the printing plates will then be stuck to one of the drawsheets and another of the plates will be located in a similar position on the other drawsheet with the aid of an optical system that registers an image of the second plate with the image of the first plate in a reflecting surface, the second plate being shifted about on its drawsheet until the images are in registry. When this occurs, the plates have the same relative positions on their drawsheets. Some registering apparatus have a third cylinder geared to the other cylinders to carry a proof sheet on which an impression may be made to determine registry of the images.

Such apparatus has been satisfactory as far as it goes, but it is often desirable to locate the printing plates with respect to the original composition from which the printing plates were made, or it may be that the printing must appear as on an article printed during a former job, for example, an envelope. The composition by which the plates are located is a positive, whereas the printing plates are negative, or in reverse. Consequently, the mirror systems of present registering apparatus are not satisfactory to register a positive image with a negative image, because the eye of the operator would see one image in reverse to the other. It is the present practice to convert the positive composition to a negative, so that it corresponds to the plate. It is obvious that this involves considerable additional work and expense.

Also, with the present apparatus it is impossible to simultaneously check accuracy of the surface of the printing plates and produce a proof before applying the plates on the cylinders of the press. It is also desirable to check andcorrect the accuracy of the plates in the registering apparatus, because in many instances, when dealing with nonrigid plate material, mounting of the plate on the drawsheet can produce certain distortions in the overall height of the printing surface. Also, in many cases intentional distortions are required. For example, when the plate has both a solid area and an area with fine lines or light type upon it, the solid area must be made higher than the area of the fine or light type. This is because the material of the plate, being resilient, results in unequal application of pressure, and the light type areas squeeze out. Consequently, to obtain even printing, the firmer areas must be built up higher than the softer areas. Deformities may also occur in the molding process by which the plates are formed, or they can exist in the master from which the molds are made.

With the above in mind, principal objects of the present invention are to provide a registering apparatuswith an improved optical system to register printing plates with a positive copy, and to utilize the optical system in checking registry during build-up of certain areas of the printing plates on the drawsheets to see that the registry is not destroyed during readjustment of the height of the printing areas.

Other objects of the invention are to provide a registering apparatus to establish an equivalent pressure on the plates between the proof cylinder and the plate cylinder thereof; to provide means for obtaining an accurate sample of printing to be executed from the plates, as when they are applied to the cylinders of the press; and to provide a more satisfactory and quicker method of registering printing plates and adjusting them off the press for obtaining a better quality of printing and to obtain a prolonged life of the plates.

In accomplishing these and other objects of the invention as hereinafter pointed out, we have provided improved structure, the preferred form of which is illustrated in the accompanying drawings, wherein:

FIG. 1 is a vertical section through a registering and plate adjusting apparatus constructed in accordance with the present invention, the section being taken on the line 1-1 of FIG. 3.

FIG. 2 is a horizontal section through the apparatus on the line 22 of FIG. 1.

FIG. 3 is a front elevational view of the apparatus, with a portion in section.

FIG. 4 is a perspective view of one of the cylinders, showing a drawsheet applied thereon and a printing plate applied to the drawsheet.

Referring more in detail to the drawings:

The apparatus of the present invention includes a frame 1 comprising side members 2 and 3, spaced apart in .parallel relation by transverse rails 4 and 5, and a lower base plate 6. Positioned between the side members 2 and 3 on shafts 9, 1t and 11 are cylinders 12, 13 and 14. The cylinders are so located that the cylinder 12 is in an upper portion of the frame slightly toward the rear, and the cylinders 13 and 14 are located in the lower portion of the frame at a sufficient distance below the upper cylinder 12 to accommodate an optical system and a lower work space therebetween, generally designated by the numerals 15 and 15', to be later described. The shafts 9 and 10' of the cylinders 12 and 13 are journaled in sets of bearings 7 and 8 that are directly fixed to the side frame, but the shaft 11 for the cylinder 14 is independently movable for adjusting the cylinders to and from each other, for a purpose to be later described. The cylinders 12 and 13 are linked together so that they will rotate or oscillate in unison, for example, by means of a chain 16 operating over sprockets 17 on projecting ends 18 of each of the shafts 9 and 10. One of the shafts, for example, the shaft 10, may have a driving means connected therewith, such as a hand wheel 19, by which the cylinders may be oscillated or rotated as required.

In carrying out the present invention, the cylinders 12 and 13 have a row of pins 20 extending longitudinally of one side thereof and in spaced apart relation exactly corresponding with similar pins on the cylinders (not shown) of a printing press, 50 that mounting of draw-sheets 21 and 22 can accurately be positioned on the cylinders 12 and 13 in the same relative position that the drawsheets will have when placed on the cylinders of the press. The drawsheets 21 and 22 may be rubber blanks, tympan sheets, Mylar sheets, or any sheets whichtare reasonably dimensionally stable and which are provided with a row of holes 23 (FIG. 4) along one marginal edge, to fit over the .pins 20 and be extended around the surfaces of the cylinders so that their opposite marginal edges may be secured to the surface of the cylinder by strips of adhesive tape 24, as best illustrated in FIG. 4. The drawsheets, when thus mounted on the cylinders, are always positioned in the same relative locations on the respective cylinders, to give immediate, accurate positioning thereof.

As above stated, it is an object of the present invention to utilize a composition, such as a drawing, photograph, or a previously printed article saved from a former job; for example and by way of illustration, an envelope, which will be called a dummy 25 (FIG. 1). The envelope will, therefore, have positive printed areas thereon in different colored inks, or the inks may have been applied in registry to produce the colors and tones thereof, as for example, of a colored photograph or drawing, and it is desired that the printing on the present envelopes should be located in exact conformity with the envelopes of the previous job. The dummy envelope is applied to the drawsheet of the upper cylinder by taping thereof to the surface of the drawsheet, as illustrated in FIG. 1, by means of strips of adhesive 26 to hold the dummy smoothly against the surface of the sheet, to aid in positioning printing plates .27, previously used or made in accordance with any method, as it forms no part of the present'invention.

The only requirement is that the plates can be readily curved about the curvature of the drawsheet on the cylinder 13 and fastened thereto by means of a double-coated adhesive. Such plates are usually made of a resilient material, like rubber or rubber composition or the like, ca-

pable of having the ink or type areas formed thereon in any desired manner. In order to readily stick the plates to the drawsheets, the plates may have adhesive 23 applied to the backs thereof, which is capable of adhering to the surface of the drawsheet or an adhesive applied thereon.

The optical system 15 for registering the negative image of the plate and positive image of the dummy must provide for converting one of the images, so that the images are the same. To accomplish this, the optical system has three mirrors 29, 30 and 31 carried in a housing 32 which is positioned between the side members 2 and 3 of the frame 1. The housing 32 may correspond in width to the length of the cylinders, however, if exceptionally long cylinders are used, the housing may be narrower and mounted for movement along the rails 4 and 5, to the positioned relative to the printing areas. The housing 32 consists of side plates 33 and 34, each having sets of bars 35 and 36 fixed to the plates for engaging the ends of the mirrors therebetween, to hold the mirrors at a proper angle and position to register the images, as now to be described.

The mirrors 29 and 30 are aligned horizontally in the frame below the cylinder 12, with the mirror 30 located in front and the mirror ,29 to the rear of the cylinder 12 and positioned on substantially parallel planes, so that the mirror 29 is in position to reflect the light rays from the dummy 25 to be reflected horizontally through the mirror 30, which is a transparent mirror, to the eye of the operator. The mirror 31 is located above and in front of the mirror 30 and positioned at an angle, so that light rays from the printing plate will be reflected by the mirror 31 onto the mirror 30 and be reflected therefrom into a horizontal direction like the reflections from the mirror 29.

In order to control the light on the respective sides of the transparent mirror 30, the housing 32 has a cover 37 that extends over the mirror 30 from a point spaced from the mirror 29 and upwardly around the mirror 31, to terminate in substantially horizontal alignment with the upper edge of the mirror 30. The rear end of the cover 37 cooperates with the upper edge of the mirror 30 and provides an opening 38 for passing the light rays from the dummy onto the mirror surface of the mirror 29. The rear edge of the cover is supported on a bar 39 and the front by a rod 40, each of which has ends supported by the side plates 33 and 34. The bottom of the housing between the mirrors 29 and 30 is closed by a plate 41 having flanged ends 42 fixed to the side plates 33 and 34. Cooperating with the front terminal edge of the cover 37 and spaced therebelow is a shield 43 having a downwardly extending portion 44 and a forwardly extending horizontal portion 45. The downwardly extending portion 44 cooperates with the lower edge of the mirror 30 to provide an opening 46 therebetween, and the portion 45 provides the bottom of a sight opening 47 through which the images on the mirrors 29 and 30 are viewed.

The dummy 25 on the drawsheet of the upper cylinder is illuminated by a light source 48 extending along the rear side of the opening 38, and the plate on the drawsheet of the cylinder 13 is illuminated by a similar light source 49 located immediately below the bottom plate 41. The correct transparency for the transparent mirror 30 is obtained by adjusting the relative intensities of the two light sources 48 and 49 so that the image on the mirror 29 will be visible through the transparent mirror 30, while the image of the printing plate on the cylinder 13 will be visible upon the reflecting surface of the transparent rnirror, whereby both images may be seen and registered with one another by arranging the position of the printing plate on the cylinder 13. For example, if

the dummy 25 on the cylinder 12 is positive, it will make a negative image on the mirror 29, and the eye 50 of the operator will see that image through the transparent mirror 30. The image for the printing plate 27 on the cylinder 13 will appear as a positive in the mirror 31, but when reflected on the transparent mirror 30, it will appear as a negative, so that it can be easily registered with the image on the mirror 29 by shifting the plate 27 on its drawsheet 22 until registry occurs, whereupon the printing plate is adhered to the cylinder 13.

In order to prevent the parallax, the light path distance from a point on the dummy 25 to the eye 59, as indicated by the lines 51 and 52, is equal to the light path distance from a point on the printing plate 27 to the eye 51 as indicated by the lines 53, 54 and 55, the line 55 being in coincidence with the line 52,

In addition to the accurate positioning of the plates in relation to the cylinders on the press, and in relation to other colors on multi-color equipment, the plates must yield a uniform printed image. As above stated, the plates 27 may, for various reasons, vary in thickness, so that uneven printing occurs because the low printing areas of the plate do not take the ink. The present invention contemplates correction of this difiiculty by building up the low areas on the under surface of the plate 27 on the drawsheet 22 while a plate is in the registering apparatus. The present invention also contemplates making whatever intentional distortions are necessary so that both the solid areas and the areas having the fine type will take the proper amount of ink to print uniformly, as now to be described.

In carrying out this part of the invention, the cylinder 14 is mounted in such a way that the center-tocenter distance between the axes of the cylinders 13 and 14 can be accurately controlled. This may be accomplished by journalin-g the ends of the shaft 11 in eccentric bearings connected with an accurately controlled linkage which will allow the surface of the cylinder 14 to be moved to and from the surface of the plate carried by the cylinder 13, a distance, for example, of .001 inch or less at a time. One simple method of obtaining this result is to mount the bearing brackets 56 and 57 which journal the shaft 11 on slides 58 and 59 that are fixed to the side frame members 2 and 3, as shown in FIGS. 1 and 3. The brackets 56 and 57 are connected by a crossbar 60 having a lug 60 provided with an internally finely threaded bore 61 in which threads 62 on an adjusting shaft 63 are engaged. The opposite end 64 of the shaft 63 is journaled in a transverse rail 65 carried by the front edge of the base plate 6. The shaft is retained from axial movement 'by a collar 66 and a disk 67 fixed to the shaft and engaging respective sides of the rail 65. The journaled end of the shaft also has a handcrank 68 by which the shaft may be turned for moving the cylinder 14 to and from the cylinder 13. The disk 67 is preferably provided with a circumferential scale 69 by which adjustments of the cylinder 14 may be noted.

The cylinder 14 will be rotated from the cylinder 13 through a transmission means which will give them uniform and equal surface speeds in opposite directions. That is, when the cylinder 13 is rotated in an anticlockwise direction, the cylinder 14 will be rotated in a clockwise direction (FIG. 1). One such means is illustrated as gears 70 and 71 on the respective cylinders 13 and 14, having intermeshing teeth capable of maintaining a driving connection throughout the slight adjustment that is necessary between the surfaces of the cylinders.

In order to show up errors in the printing plate and to determine what portions of the plate must be built up to take a uniform impression, the printing plate may be inked by means of a hand roller. However, the registering apparatus is preferably equipped with a mechanical inking unit 72 which includes an ink pickup roller 73 rotatably mounted in an ink pan 74. Also rotatable in the ink pan 74 in rolling contact with the pickup rollers 73, but out of the ink 75, is an ink applicating roller 76. The unit 72 is preferably mounted between the roller 13 and the rail 65 in a position for the applicating roller 76 to contact the printing surface of the plate 27. The inking unit 72 is preferably removably mounted in fixed position along the inner side of the rail 65 upon a seating means indicated by the numeral 77.

The inking unit 72 is well adapted for applying aniline or fiexographic inks, which inks are most desirable because they inherently tend to show up errors in the printing plate 27 much more quickly than so-called oil base inks. With the use of aniline or flexographic ink, a variation in plate height more than .0015 inch can be detected very readily by inspecting the ink film on the surfaces of the printing plate. If the printing surfaces of the plate are satisfactory, they are all uniformly coated. However, if portions of the plate fail to receive ink, then those portions must be built up between the plate 27 and the drawsheet 22 until all printing areas are receiving an ink coating.

By turning the cylinder 13, the plate is brought into rolling contact with the surface of a paper sheet 78 that has been applied to the surface of the cylinder 14 by adhesive tape 79, to make an ink impression on the paper for checking the hard and soft printing areas on the plate in accordance with pressure conditions that Will exist in the printing press.

The soft areas, such as those containing fine lines or type, may be readily noted and inserts may be added to the drawsheet under the hard areas to compensate for the excess pressure of the soft areas until a clear and uniform ink image is obtained on the paper sheet. This may take several trials, during which portions of the plate 27 must be lifted from the surface of the drawsheet 22 on the cylinder 13 and replaced after each make-ready test. The operator may be assured that registry has not been disturbed with respect to the dummy 25 on the cylinder 12 by noting any off-alignment of the images on the mirrors 29 and 30.

The calibration 69 of the dial 67 indicates the centerto-center distance between the cylinders 13 and 14 that is required to give the desired squeeze pressure. The total squeeze on the rubber plate cannot exceed .002 inch if the plate is to be used for flexographic printing, and .005 inch if it is to be used subsequently With an oil ink letterpress printing unit. As a matter of fact, minimizing the amount of squeeze is always desirable, as it prolonges plate life. In theory, rubber plate printing should be done from a kiss impression, meaning a squeeze of less than .002 inch.

After locating and making-ready one plate, the drawsheet carrying that plate is removed from the cylinder 13 and another drawsheet is applied, for similarly locating and making-ready a plate for another color. The plate will also be registered with the dummy 25, so that when the registration is complete and the plate is made-ready, it will have the same relative position on its drawsheet as the previous plate. The process is repeated for the other plates that may be required.

It is obvious that if a customer desires a sample of the printing job, a fully colored reproduction may be produced on a paper sheet applied to the cylinder 14 of the registering apparatus.

When changing from one color to another, the pickup and applicating rollers are easily cleaned by wiping them off with a solvent. However, for convenience, the pan 74 might be provided with removable pan inserts, each adapted to contain an individual color, or type of ink. In this way, one insert is removed and replaced by an insert containing ink of another color.

What we claim and desire to secure by Letters Patent 1. The method of registering and making-ready a printing plate while off of a press with a master dummy in a registering apparatus which has separated cylinders for the dummy and printing plate and a proofing cylinder movable into contact with the plate and wherein the printing plate is reverse reading to the dummy, and including an optical system between the separated dummy and printing plate cylinders for registering a singly reflected image from the dummy and a doubly reflected image of the printing plate to the eye or" the operator, said method including the steps of securing a drawsheet from the press onto the printing plate cylinder and a corresponding drawsheet on the cylinder for the dummy in exactly the same relative position, fixing the dummy to the drawsheet which has been secured to the cylinder for the dummy, viewing from a first reflector the singly reflected image of the dummy through a semi-transparent reflector from the space between said printing plate cylinder and dummy cylinder, simultaneously viewing the doubly reflected image of the plate from a second reflector and said semi-transparent reflector, shifting the printing plateupon the other drawsheet until a position is found where the doubly reflected image of said printing plate registers with the singly reflected image of the dummy, fixing the printing plate in said registering position on said drawsheet, and making-ready the printing areas of said plate while on said printing plate cylinder in the registering apparatus by retaining the dummy fixed on its drawsheet on the cylinder for the dummy throughout the time of making-ready and applying ink to the printing surfaces of the printing plate while registered on the drawsheet on the printing plate cylinder, applying a proof sheet on a proofing cylinder contactable with the cylinder for the printing plate and spaced from said dummy cylinder, applying a squeezing pressure between the proof sheet and the printing plate cylinder without contacting the dummy cylinder with either of the other cylinders, turning the printing plate and proofing cylinders to produce an ink impression on the proof sheet for determining areas on the plate where the fine detail tends to squeeze out, building up the printing plate on its drawsheet under the harder areas to obtain uniform transfer of ink from all parts of the printing plate while said drawsheet is on the printing plate cylinder, and retesting registry of the printing plate image with the image of the dummy while retaining the printing plate in said apparatus at the place of building up of the printing plate on its drawsheet. 2. The method as set forth in claim 1 wherein said squeezing pressure is measured.

3. An apparatus for registering and making-ready printing plates off a press, said apparatus including,

a main frame, spaced-apart cylinders journalled on the main frame to oscillate on parallel axes, drawsheets, means for securing a drawsheet in the same relative position upon each of the cylinders, means for securing a master dummy, which is reverse reading to the plate, to the drawsheet on one of the cylinders on a radius,

means for securing the plate to the drawsheet on the other of the cylinders whereby the plate surfaceis on an equal radius,

a driving connection between the cylinders to keep the cylinders in the same rotational relation,

an optical system on said frame and interposed within the space between said cylinders, said optical system including a first reflector positioned to reflect an image directly from the dummy to a sight path extending between said cylinders and intersecting the plane containing the axes of said cylinders,

said optical system including a semi-transparent reflector located in said sight path and transmitting said dummy image therethrough,

said optical system including a second reflector positioned to reflect an image directly from the printing plate, when positioned upon the drawsheet on the other cylinder, to said semi-transparent reflector, said semi-transparent reflector being positioned to reflect said last named image into said sight path,

means securing the printing plate to said other drawsheet when the images appear in registry on said path, and

means carried by the main frame near the said other cylinder for applying an ink film to the printing areas of the printing plate, a proofing cylinder mounted on said main frame for movement into engagement with said other cylinder, said optical system being between said one cylinder and said proofing cylinder, whereby the registration of the images may be checked and rechecked during make-ready while the printing plate remains in said other cylinder.

4. The apparatus as set forth in claim 3 wherein said proofing cylinder is mounted by means adapted to apply a predetermined squeeze pressure between said proofing cylinder and said other cylinder.

5. An apparatus for registering and makingready printing plates off a press as described in claim 3, wherein the ink applying means includes an applicating roller for contact with the printing areas of the printing plate for applying a film of ink,

an ink container extending longitudinally of the applicating roller, and

an ink pickup roller within the container in rolling contact with the applicating roller for picking up ink from the container and distributing the ink on the applicating roller.

References Cited UNITED STATES PATENTS 626,031 5/1899 Osborne 101-174 X 1,524,071 1/1925 White 101-426 2,082,372 6/ 1937 Wood 101-174 2,355,529 8/1944 Hawley 101-401.3 2,492,798 12/ 1949 Harley 101-426 2,561,115 7/1951 Harley 101-426 2,701,521 2/1955 Taylor 101-426 3,186,336 6/1965 Kirby 101-216 ROBERT E. PULFREY, Primary Examiner.

J. R. FISHER, Assistant Examiner. 

3. AN APPARATUS FOR REGISTERING AND MAKING-READY PRINTING PLATES OFF A PRESS, SAID APPARATUS INCLUDING, A MAIN FRAME, SPACED-APART CYLINDERS JOURNALLED ON THE MAIN FRAME TO OSCILLATE ON PARALLEL AXES, DRAWSHEETS, MEANS FOR SECURING A DRAWSHEETS IN THE SAME RELATIVE POSITION UPON EACH OF THE CYLINDERS, MEANS FOR SECURING A MASTER DUMMY, WHICH IS REVERSE READING TO THE PLATE, TO THE DRAWSHEET ON ONE OF THE CYLINDERS ON A RADIUS, MEANS FOR SECURING THE PLATE TO THE DRAWSHEET ON THE OTHER OF THE CYLINDERS WHEREBY THE PLATE SURFACE IS ON AN EQUAL RADIUS, A DRIVING CONNECTION BETWEEN THE CYLINDERS TO KEEP THE CYLINDERS IN THE SAME ROTATIONAL RELATION, AN OPTICAL SYSTEM ON SAID FRAME AND INTERPOSED WITHIN THE SPACE BETWEEN SAID CYLINDERS, SAID OPTICAL SYSTEM INCLUDING A FIRST REFLECTOR POSITIONED TO REFLECT AN IMAGE DIRECTLY FROM THE DUMMY TO A SIGHT PATH EXTENDING BETWEEN SAID CYLINDERS AND INTERSECTING THE PLANE CONTAINING THE AXES OF SAID CYLINDERS, SAID OPTICAL SYSTEM INCLUDING A SEMI-TRANSPARENT REFLECTOR LOCATED IN SAID SIGHT PATH AND TRANSMITTING SAID DUIMMY IMAGE THERETHROUGH, SAID OPTICAL SYSTEM INCLUDING A SECOND REFLECTOR POSITIONED TO REFLECT AN IMAGE DIRECTLY FROM THE PRINTING PLATE, WHEN POSITIONED UPON THE DRAWSHEET ON THE OTHER CYLINDER, TO SAID SEMI-TRANSPARENT REFLECTOR SAID SEMI-TRANSPARENT REFLECTOR BEING POSITIONED TO REFLECT SAID LAST NAMED IMAGE INTO SAID SIGHT PATH, MEANS SECURING THE PRINTING PLATE TO SAID OTHER DRAWSHEET WHEN THE IMAGES APPEAR IN REGISTRY ON SAID PATH, AND MEANS CARRIED BY THE MAIN FRAME NEAR THE SAID OTHER CYLINDER FOR APPLYING AN INK FILM TO THE PRINTING AREAS OF THE PRINTING PLATE, A PROOFING CYLINDER MOUNTED ON SAID MAIN FRAME FOR MOVEMENT INTO ENGAGEMENT WITH SAID OTHER CYLINDER, SAID OPTICAL SYSTEM BEING BETWEEN SAID ONE CYLINDER AND SAID PROOFING CYLINDER, WHEREBY THE REGISTRATION OF, THE IMAGES MAY BE CHECKED AND RECHECKED DURING MAKE-READY WHILE THE PRINTING PLATE REMAINS IN SAID OTHER CYLINDER. 